Search Publications
The Chandra Deep Protocluster Survey: Lyα Blobs are Powered by Heating, Not Cooling
Ivison, R. J.; Lehmer, B. D.; Smail, Ian +11 more
We present the results of a 400 ks Chandra survey of 29 extended Lyα emitting nebulae (Lyα Blobs, LABs) in the z = 3.09 protocluster in the SS A22 field. We detect luminous X-ray counterparts in five LABs, implying a large fraction of active galactic nuclei (AGN) in LABs, f AGN = 17+12 -7% down to L 2-32 keV <…
Hubble Space Telescope Weak-lensing Study of the Galaxy Cluster XMMU J2235.3 - 2557 at z ~ 1.4: A Surprisingly Massive Galaxy Cluster When the Universe is One-third of its Current Age
Böhringer, H.; Ford, H. C.; Demarco, R. +8 more
We present a weak-lensing analysis of the z sime 1.4 galaxy cluster XMMU J2235.3 - 2557, based on deep Advanced Camera for Surveys images. Despite the observational challenge set by the high redshift of the lens, we detect a substantial lensing signal at the gsim8σ level. This clear detection is enabled in part by the high mass of the cluster, whi…
Properties of Magnetohydrodynamic Waves in the Solar Photosphere Obtained with Hinode
Tsuneta, S.; Fujimura, D.
We report the observations of the magnetohydrodynamic (MHD) waves propagating along magnetic flux tubes in the solar photosphere. We identified 20 isolated strong peaks (8 peaks for pores and 12 peaks for intergranular magnetic structure) in the power spectra of the line-of-sight (LOS) magnetic flux, the LOS velocity, and the intensity for 14 diff…
The Extreme Microlensing Event OGLE-2007-BLG-224: Terrestrial Parallax Observation of a Thick-Disk Brown Dwarf
Lee, C. -U.; Fouque, P.; Bennett, D. P. +75 more
Parallax is the most fundamental technique for measuring distances to astronomical objects. Although terrestrial parallax was pioneered over 2000 years ago by Hipparchus (ca. 140 B.C.E.) to measure the distance to the Moon, the baseline of the Earth is so small that terrestrial parallax can generally only be applied to objects in the Solar System.…
Detection of Gamma-Ray Emission from the Eta-Carinae Region
Antonelli, L. A.; Pian, E.; Costa, E. +63 more
We present the results of extensive observations by the gamma-ray AGILE satellite of the Galactic region hosting the Carina nebula and the remarkable colliding wind binary Eta Carinae (η Car) during the period 2007 July-2009 January. We detect a gamma-ray source (1AGL J1043-5931) consistent with the position of η Car. If 1AGL J1043-5931 is associa…
Hubble Space Telescope Observations of a Spectacular New Strong-Lensing Galaxy Cluster: MACS J1149.5+2223 at z = 0.544
Richard, Johan; Smith, Graham P.; Smail, Ian +9 more
We present Advanced Camera for Surveys observations of MACS J1149.5+2223, an X-ray luminous galaxy cluster at z = 0.544 discovered by the Massive Cluster Survey. The data reveal at least seven multiply imaged galaxies, three of which we have confirmed spectroscopically. One of these is a spectacular face-on spiral galaxy at z = 1.491, the four ima…
Local Lyman Break Galaxy Analogs: The Impact of Massive Star-Forming Clumps on the Interstellar Medium and the Global Structure of Young, Forming Galaxies
Heckman, Timothy M.; Rich, R. Michael; Seibert, Mark +10 more
We report on the results of Hubble Space Telescope optical and UV imaging, Spitzer mid-IR photometry, and optical spectroscopy of a sample of 30 low-redshift (z ~ 0.1 to 0.3) galaxies chosen from the Sloan Digital Sky Survey and Galaxy Evolution Explorer surveys to be accurate local analogs of the high-redshift Lyman break galaxies. The Lyman brea…
Active Region Transition Region Loop Populations and Their Relationship to the Corona
Warren, Harry P.; Ugarte-Urra, Ignacio; Brooks, David H.
The relationships among coronal loop structures at different temperatures are not settled. Previous studies have suggested that coronal loops in the core of an active region (AR) are not seen cooling through lower temperatures and therefore are steadily heated. If loops were cooling, the transition region would be an ideal temperature regime to lo…
High-Redshift Quasars in the COSMOS Survey: The Space Density of z > 3 X-Ray Selected QSOs
Ilbert, O.; Salvato, M.; Merloni, A. +19 more
We present a new measurement of the space density of high-redshift (zsime 3.0-4.5), X-ray-selected quasi-stellar objects (QSOs) obtained by exploiting the deep and uniform multiwavelength coverage of the COSMOS survey. We have assembled a large (40 objects), homogeneous sample of z > 3 QSOs with X-ray flux F 0.5-2 keV > 10-15…
Isotropic Luminosity Indicators in a Complete AGN Sample
Rieke, George H.; Rigby, Jane R.; Diamond-Stanic, Aleksandar M.
The [O IV] λ25.89 µm line has been shown to be an accurate indicator of active galactic nucleus (AGN) intrinsic luminosity in that it correlates well with hard (10-200 keV) X-ray emission. We present measurements of [O IV] for 89 Seyfert galaxies from the unbiased revised Shapley-Ames (RSA) sample. The [O IV] luminosity distributions of obsc…